Na Quan Fm
Period:
Devonian
Age Interval:
Emsian-Eifelian, (3)
Province:
Viet Bac
Type Locality and Naming
Stratotype in the Na Quan – Bang Ca – Ban Thoang section in the Ha Lang area (Cao Bang Province); named and described by Duong Xuan Hao, 1968; Pham Dinh Long, 1974.
Lithology and Thickness
Stratotype has 320 m of thin- to thick-bedded limestone containing chert components in different levels.
Lithology Pattern:
Siliceous limestone
Relationships and Distribution
Lower contact
Conformable on the Mia Le Fm
Upper contact
Conformable under the Ban Cong Fm
Regional extent
Within the Cao Bang Province
GeoJSON
null
Fossils
Rich collection of corals, plus brachiopods.
Age
Fossils date the formation as Emsian (Early Devonian) to Givetian (Middle Devonian)
Age Span:
Beginning stage:
Emsian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
410.51
Ending stage:
Eifelian
Fraction up in the ending stage:
1.0
Ending date (Ma):
385.30
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Tran Van Tri and Vu Khuc (Editors; Geology and Earth Resources of Viet Nam, General Dept. of Geology and Minerals of Viet Nam; completed in Dec., 2011), with additional details from Tong-Dzuy Thanh and Vu Khuc (Editors; Stratigraphic Units of Viet Nam, 2nd edition; 2011; English edited by A. Boucot).